In what context ?
For an average homeowner doing their own backup plan, 10kVA is going to be a bit overkill - a large, heavy, and expensive machine that's going to get little (if any) use. On the other hand, I know a few farmers who have something like 25kVA generators (especially the ones in the middle of nowhere with lots of overhead lines) - but they have the advantage of not needing to buy the engine part as they can drive it from a tractor.
Where I worked a good few years ago now, we went through a phase of having a lot of power cuts - being on the end of a very long string of overhead lines etc. Incidentally I noted that they tended to be of 3 distinct durations - a few seconds (auto-reclose), a few minutes (manual remote reclose), or 90 minutes. It was notable that we had several outages of 90 minutes - not 85 or 95, but 90. I speculated that the engineers were given a target time of 90 minutes, and having a relative in the industry knew that there was "some friction" between manglement and engineers over working practices - so suspected that even if thy were able to turn out, get to the substation, and reclose the breaker in (say) 80 minutes, they'd leave it till 90 minutes so as not to give manglement an excuse to demand 80 minutes next time. But I digress ...
Every time the lights went out, our manglement would ask "how much for a generator ?" - to which we (myself on the IT and tech services side, the maintenance manager from the production side) would ask "to run what ?" We never really got an answer to that, or to how they'd determine what were "critical" loads - the whole site had it's own 500kVA transformer, so they definitely didn't want to pay for a genny that size even though it would have been by far the easiest and simplest option to install - these days I'd be pushing for that, with paralleling capability, and earn some income for STOR
Needless to say, once the power was back on, manglement would forget about it. The maintenance manager got to the point of just keeping the last quote (for a small one, just to run key IT stuff) handy so he could just copy it and drop it on the directors desk each time he was asked
At one point someone asked the DNO about a second feed form the village - quite literally we'd be in the dark but could see the lights on just 50m down the road. The quote was "significant" - but what killed it was the realisation that if we were off, the DNO engineers would only get round to coming and switching us over after they'd been to sort out the fault that took us (and a few other villages) off in the first place.